Make shorter a script

[fzs1933]

I would like to make a bigger video to show the seasons night sky and wrote a script which looks to good for this purpose.
But it is too long and my programming knowledge is too little to make it simply.
I need help to take this step.

https://github.com/fzs1933/seasons/blob/78422eba0c11eef7cad9a744bd721a93873e03df/nyar_beta.ssc

I emphasize again, my programming knowledge actually approximate to zero.
Thanks a lot for all help/answer.
Zsolt

[alex-w]

See "Largest known stars" or "Binocular highlights" scripts for example.

[fzs1933]

This:
core.setDate("2021-03-21T11:00:00", "UTC");
core.setTimeRate(0);
core.wait(3);
core.setTimeRate (7200);
core.waitFor("2021-03-21T23:00:00", "UTC");
core.setTimeRate (0);
core.wait(1);

Always different the results... Why? What am I doing wrong?

[alex-w]

Please describe the behaviour of the script, which you want to get (what should be happening between those dates?)

[fzs1933]

Thanks your answer!
So, I am looking south. I can see the Sun at 2021-02-21T11:00:00. I want to simulate a half day with exact times.
And I want to rotate the sky to 2021-02-21T23:00:00. Let the rotation be 10 seconds. It is important to the start time and the end time be exactly.
I hope it is clear and enough informations... :)

[fzs1933]

Upper pic is the start
You can see that after two script runs the stop time are not exactly 23:00:00 and not consistent.

[fzs1933]

For last.
If the exactly stopping cannot be solved, I will use this method. Could the time equation be confusing? (I switched it off)
Although I thought 43200 seconds is 43200 seconds, regardless of the length of the actual day length.

I make a long video about the nightsky and I would like to export it with the fewest cut. As it possible, there will be only one script and this is why the exact times are very important for me.